Functions

A function is a

block of code…

…that performs a specific task

Python already has lots of built in functions…

print() range () type() sleep()

We can declare our own functions to do what we want! These are called user-defined functions.

Let’s create a new user-defined function that will output a greeting.

Understand the different parts…

def Greeting(name): print('Hello ' + name)

Greeting(‘Sue’)

DefineFunction Name

Parameter List i.e. the inputs to the function!

Function CallHere is the ‘argument(s)’ passed to the function

Why won’t this compile?

def Message(name): print(‘How are you today' + name)

Message(‘Danny’)

Why won’t this compile?

Def Message(name): print(‘How are you today' + name)

Message(‘Danny’)

def

Understand the different parts…

def sum(num1,num2): return num1+num2

sum(12,10)

>> 22

By default, all functions should return a value.

In this case, we want our sum function to return the sum of any two numbers.

parameters

call

arguments

Function name

Function output

Another example of a function…

Note, use print here…to output the result of the function on screen…eventhough the function has already worked it out!

TASK Celsius to Fahrenheit•Prompt the user for a temperature in CELSIUS.

To convert a temp from Celsius to Fahrenheit, use the following formula:

°C  x  9/5 + 32 = °F

(Remember BEDMAS from your mathematics lessons!)

•Create a function that, when called, will calculate the temperature in Fahrenheit and return it to the main program (from where the function call was made) e.g.

Temperature conversion complete - the reading is 42 Fah

Check whether your program is accurate by checking it against the following:

Enter 30 Cel Program should output 86 Fah

TASK Fahrenheit to Celsius•Prompt the user for a temperature in Fahrenheit.

To convert a temp from Fahrenheit to Celsius use the following formula:

(°F  -  32)  x  5/9 = °C

(Remember BEDMAS from your mathematics lessons!)

•Create a function that, when called, will calculate the temperature in Celsius and return it to the main program (from where the function call was made) e.g.

Temperature conversion complete - the reading is 18 Cel

Check whether your program is accurate by checking it against the following:

Enter 86 Fah Program should output 30 Cel